using System;
namespace yukicoder
{
    class Program
    {

        static void Main(string[] args)
        {
            var S = Console.ReadLine();
            string str, str2;
            var x = S.Split();
            string[] z = new string[S.Length];
            //文字分割
            for (int j = 0; j < S.Length; j++)
            {
                z[j] = x[0].Substring(j, 1);
            }
            
            for (int i = 0; i < S.Length; i++)
            {
                string upper = z[i].ToUpper();
                string lower = z[i].ToLower();
                if (z[i].Equals(upper))
                {
                    Console.Write(lower);
                }
                else if (z[i].Equals(lower))
                {
                    Console.Write(upper);
                }
            }
        }
    }
}